Internal links in markdown not working?

[dealmeidavf]

My internal links do not work anymore. Initially I thought was the move to Notebook 7 but they do not work on Notebook 6.5.7.
I use firefox with nb 7 (on Gentoo Linux) and safari with nb 6.5.7 (on macOS Ventura).

On a markdown cell I do:

Power system block diagrams

Then later on the notebook on another cell:

Power System Block Diagrams

Clicking on the link above Power system block diagrams does not move the cursor down to the Power System Block Diagrams section.

Thanks for inputs.

Valmor